North Korea's reported nuclear test explosion is drawing international condemnation.

China, the North's only major ally, issued a statement criticizing Pyongyang for carrying out a test with "disregard" for international objections. The statement said China "resolutely opposes" the test and calls on North Korea to stop any behavior that "worsens the situation."

France strongly condemned the nuclear test. It called on the United Nations Security Council to quickly face the issue.

The head of the International Atomic Energy Agency said North Korea's nuclear test, if confirmed, is in clear violation of numerous U.N. Security Council resolutions and in complete disregard of the repeated demands of the international community.

U.S. Secretary of State John Kerry, in Geneva, expressed deep concern. Kerry said the U.S. is still trying to determine precisely what happened.